Method of incorporating metal salts of color couplers in photographic emulsions



United States Patent Ofitice 3,080,233 Patients;d Mar. 5, 1963 Curt B.Roth and Fritz W. H. Mueller, Einghamton,

N .Y., asisguors to Generai Anilinedz Film Corporation, New York, N.Y.,a corporation er Delaware I No Drawing. Filed Apr. 3%), 1959, filer.809326 This invention relates to color photography and in particular tophotographic emulsions for color photography containing the alkali metalsalts of color formers or couplers incorporated therein by means ofWater miscible solvents.

Photographic emulsions are described containing thereina couplercompound of the type capable of coupling with the oxidation products ofa primary aromatic amino developing agent whereby is produced a coloredphotographic image. In the manufacture of such emulsions, there are avariety of Ways in which the coupler compounds can be incorporatedtherein. In one preferred method, an aqueous solution of the couplercompound is dissolved directly in the hydrophilic colloid of thephotographic emulsion. Such couplers commonly contain, in addition to anon-difiusing group, a sulfonic acid or carboxylic acid grouping and areemployed in the form of their alkali metal salts. I

However, there are certain dililculties which are frequently encounteredin carrying out the aforesaid procedures. Thus, certain of the abovecouplers are soluble only in highly alkaline solutions which are toobasic for incorporation in conventional light sensitive silver halideemulsions.

Another difficulty attendant to the use of couplers of this type can beattributed to the presence of the non-diffusing group. The presence ofthis long aliphatic chain, in combination with a salt-forming group inthe coupler molecule, customarily increases the viscosity of thephotographic emulsion resulting in coating difficulties.

It is, therefore, an object of the present invention to provide a novelmeans of incorporating the alkali metal or ammonium salts of colored orcolorless couplers containing acidic groups in photographic emulsions.

It is a further object to provide a method of incorf porating the alkalimetal salts of couplers containing acid groups in photographic emulsionswithout increasing the viscosity of said emulsions.

It is a still further object to provide a method of incorporating thealkali metal and ammonium salts of such couplers without resorting toconditions of high basicity or alkalinity.

Other objects will appear hereinafter as the description of ourinvention proceeds.

The aforesaid objects can be accomplished by dissolving a color couplerof the type described herein in the form of its alkali metal salt in awater soluble or water miscible solvent for said alkali metal couplersalt and dispersing the resulting solvent solution of the coupler saltin a photographic colloid. The Water soluble or Water miscible solventis then removed from the alkali metal coupler salt dispersionincorporated in a hydrophilic colloid silver halide emulsion.

The dispersions of the alkali metal coupler salts obtained as describedabove consist of extremely finely divided particles which display notendency to settle out or coalesce. Such dispersions of alkali metalcoupler salts can be stored indefinitely in the chilled state prior tothe coating operation.

As previously pointed out, the couplers used in our process arecharacterized by the presence of a salt-form- 2 ing group, i.e., acarboxylic acid or sulfonic acid group, and a non-difiusing group suchas an aliphatic chain of at least 10 carbon atoms. Such couplers arefurther characterized in that their alkali metal salts are notsufficiently soluble in aqueous systems or require prohibitively high pHvalues in order to eifect their incorporation directly in a hydrophilicphotographic colloid. Couplers which we have found particularly suitablein this connection contain, as the non-diffusing group, an alkyl radicalof at least 10 carbon atoms in which a salt-forming radical is locatedon the terminal carbon atom of said alkyl group. These couplers can bedepicted by the following general formula:

CO-NHR wherein M represents a hydrogen, ammonium or an alkali metal, Rrepresents a coupler molecule of the type containing a reactivemethylene or phenolic hydroxy group, andn n represents a positiveinteger of 9 or more.

By reactive methylene group is meant the type commonly encounteredincolor couplers and which can be depicted by the following generalformula:

wherein X arid Y stand for electron attracting groups such as carbonyl,cyano, nitr'o and the like. By'pheriolic hydroir'y group is meant thephenolic phe'uyl' gfeu' 's commonly understood in the color coupler artand includes the phenolic or hydroXy naphtho'ic types having [a rea'ctive position para to the said hydroxy group, that is, a position whichis unsubstituted or which is substituted with a replaceable group. Theaforesaid groups are well recognized in the photographic fild so thatfurther discussion of such entities would be superfluous.

Structures falling within the ambit of the above general formula includethe following:

COMPOUND 1 o ON'H Q COMPOUND 4 assassa COMPOUND NZISOMOHsMoCONHCONHfil-CH3 COMPOUND 6 NQSO3(CH2)1QCONH-C-CH2 COMPOUND 7 ,-oocnzooi\rn@NHCO- -NHCO(CH2)10SO3N3 The couplers depicted formulistically above,when incorporated in a photographic emulsion and according to the methoddescribed herein, yield, on color development, exceedingly fine-grainand stable dye images and are thus valuable in the art of colorphotography.

Other couplers of the general type, whose alkali metal salts areinsoluble or require excessively high alkalinity to incorporate them ina photographic emulsion, lend themselves to our process.

According to the present invention, a photographic emulsion is preparedfor coating by adding a solution of the alkali metal salt of the couplerin a water soluble solvent directly to a melted gelatino silver halideemulsion under efiicient agitation with a laboratory type mixer such asa Waring Blendor.

It has been our experience, however, that superior results ensue when asolution of the alkali metal salt of the color former in a watermiscible solvent is first added to a gelatin solution with eificientagitation and the resultant mbrture then combined in a second operationwith the melted gelatino silver halide emulsion. The latter method isadvantageous because it avoids excessively strong agitation of the lightsensitive silver halide emulsion which can cause fog. The dispersions ofthe alkali metal salts of the couplers in gelatin may thus be combinedwith the melted gelatino silver halide emulsion using gent-1e mixing.

In one procedure, the color former is first dissolved in a watermiscible solvent such as dimethylformamide and this solution is added toan aqueous gelatin solution under vigorous agitation. The thuslyobtained mixture is then chilled, noodled and washed after which it iscom bined with a liquified photographic gelatino silver halide emulsion.The sensitive emulsion is coated after the addition of the customarystabilizers, preservatives and spreading agents in the usual manner on aconventional film base of the type commonly employed in the art such ascellulose acetate, polyester, i.e., polyethyleneterephthalate,polycarbonte, polyamide or paper, glass or the like.

In some instances, it may be desirable to remove the solvent byevaporation rather than washing of the noodled emulsion. This iselfected by coating the aforesaid photographic gelatino silver halideemulsion containing the alkali metal salt solvent solution of thecoupler and allowing the solvent to escape by evaporation during thedrying of the coated photographic emulsion. If the latter operation isfollowed, a film base should be selected of a type which is notdeleteriously eitected by the action of the water miscible solvents usedto dissolve the alkali meta-l salt of the coupler. In this connection,we have found that polyester or polycarbonate film base as well as paperor glass are suitable.

The photographic coatings prepared according to the process describedherein produce, on color development, very sharp colored images anddisplay no undesirable side effects such as desensitization or foggingduring storage or processing. It is not known, at the present time, ifthe alkali metal salt of the color former, when in corporated in ahydrophilic colloid in accordance with our invention, represents a truesolution or is in such a state of fine division as to constitute acolloidal dispersion or, perhaps, a superfine dispersion. Examples ofthe Washed emulsions have been examined under the microscope at highmagnification, i.e., in the neighborhood of 900 diameters, and there wasno evidence to indicate the presence of discrete coupler particles. Theextremely fine state of division of the alkali metal salt couplers isborne out by the virtually grainless dye images which they yield uponcolor development, that is, no dye clumps can be discerned when thedeveloped images are subjected to microscopic examination.

As stated above, the alkali metal and ammonium salts of color formers ofthe type contemplated herein are either insoluble in a photographiccolloid emulsion or require excessively high alkalinity in order toefiect their dissolution in this type of medium. Neither can suchcolor-forming components be incorporated in a photographic emulsion bythe well known lip-ophilic dispersion techniques since these couplersalts are too insoluble in the water immiscible oils commonly used forsuch lipophilic dispersion procedures. Thus, the method disclosed hereinoffers the sole means of utilizing valuable colorforming components,i.e., the aforesaid alkali metal or ammonium salts, which cannot beincorporated in a photographic emulsion by methods presently known tothe art.

As previously pointed out, the photographic emulsions containing metalsalts of color former can be prepared by two general methods. In thefirst of these methods, a di alkylformamide solution such as adimethylformamide solution of the color former is added directly to amelted gelatino silver halide emulsion While stirring with a laboratorytype mixer such as, for instance, a Waring Blendor. In the second ofthese methods, the solution of color former in dialkylformamide is firstdissolved in an aqueous solution of a hydrophilic colloid such asgelatin and the resultant mixture combined with a melted gelatino silverhalide emulsion.

The above methods produce an even distribution of color former in thecolloid carrier of the light sensitive photographic emulsionunassociated with any photographically inert material, particularly oilydispersants. That such a result should be obtained is rather startlingsince it has been our experience that attempts to mix solutions ofchemical compounds in photographic hydrophilic colloids, wherein thesolvent is water soluble, causes a precipitation of the compounds and/or a coagulation of the colloid by the solvent.

In our preferred method, the color former is first dissolved indimethylformarnide and this solution is added to an aqueous gelatinsolution and thoroughly agitated in a laboratory type mixer or stirrer.The resulting mixture is washed and then combined with a photographicgelatino silver halide emulsion, chilled and the sensitive emulsion thencoated in the usual manner on a conventional base such as that ofcellulose acetate, polyester, i.e. polyethyleneterephthalate,polycarbonate, polyamide or paper, glass or the like.

In some instances, it may be desirable to remove the dimethylformamideby evaporation rather than by washing or" the noodled emulsion. This isefiected by coating the photographic gelatino silver halide emulsioncontaining thecoupler as prepared above and allowing the di- -An evenmore surprising feature of our procedure-concerns the manner by whichthe dialkylformaim'de solution of the color former blends or mingleswith the hydrophilic photographic colloid. It was to be expected thatthe dialkylformamide solution would be dispersed or emulsified whenagitated with the hydrophilic colloid. However, examination with highpower optical equipment fails to reveal the presence of discreteparticles of the color former dispersed throughout the continuous phaseof the hydrophilic colloid. In fact, the aforesaid dialkylformamidesolutions actually appear to dissolve in the hydrophilic colloid so thatin elfect one obtains a solution of the color former salt in thehydrophilic colloid. As a consequence, a virtually grainless dye imageresults upon color development.

Photographic films prepared in accordance with the present inventionare, when wet, not very hazy or frosty in appearance, a propertycharacteristic of fihns using dispersion methods of the prior or presentart.

The following are examples of the methods used by us in incorporatingour novel color formers in photographic emulsions. The examples aregiven by way of illustration only and are not to be construed aslimiting the invention.

Example 1 This example illustrates the method used by us inincorporating a cyan color former in a photographic emulsion. Theparticular color former used in this example has the formula:

(Compound 2) 2.00 grams of the above cyan color former were dis solvedin 20 m1. of dimethylformamide. This solution was filtered and thefiltrate then mixed into 50 ml. of a 6% aqueous gelatin solution withgood stirring. A speed .mixer (Waring Blender, kitchen type) isdesirable, al-

.resulting dye in the gelatin resulting in greater sharpness, acutanceand resolution.

Example 2 720 milligrams of color former from Example 1 were dissolvedin 7 ml. of dimethylformamide, 4 drops of Tergitol NPX added and themixture filtered. Separately, a 10% aqueous solution of an inert gelatinin water was prepared at 55 C. To 30 ml. of this 10% gelatin solutionwere added 4 drops of Tergitol #4. The solution was placed into a speedmixer (Waring Blendor, kitchen type). After 30 seconds at full speed,the filtered dimethylforrnamide solution was slowly added over a periodof 30 seconds with the mixer running at 30 volts. After the twosolutions were combined, the mixer was run at full speed for 60 seconds.The milky-looking product can be used as is or the dimethylformamide canbe washed out. 'To wash the dimethylformamide out,"the emulsion waschilled, shredded and then washed by downward replacement washing for 6hours'with cold water (8 C.). The washed product was then mixed into aphotographic emulsion and evaluated as in'Examp'le 1.

Examples 3 and 4 'Thesameprocedure was followed as in Example2 but theamount of dimethylformamide used was dilferent.

Example 3 4 ml. of dimethylformarnide. Example 4 '10 m1. ofdimethylformamide.

Examples 5, '6 and 7 Three emulsionswere prepared containing thefollowing ingredients:

14.4 grams of the coupler component were dissolved in -ml. ofdimethylformamide, 10 drops of Terg'itol NPX added and the solutionfiltered. 'To a solution of 576 ml. of 10% gelatin were added 10 dropsof Tergitol #4 and the solution placed into a speed mixer. The mixer wasnow run at 10 volts for 45 seconds. Over a period of 120 seconds, thefiltered dimethylformamide solution was then added, the mixer running at15 volts. After the two were combined, the mixer was run seconds at fullspeed volts). The warm, milky emulsion was next poured into an 11 inch x14 inch photographic tray. After cooling, the emulsion was cut up andthe noodles placed into a wire basket and washed with'cold (842 C.)running water until the noodles were washed free of dimethylformamide(about 8 hours).

The use of Tergitol produces a finer dispersion of color former and dyein the gelatin. Note that no alkali was used in these examples. The useof alkali produces a yellowish looking product and is detrimental asa-rule.

The washed noodles were then added to a photographic color emulsion andcoated. Samples of coatings containing the dyes developed by the use ofthe novel color former components as in the above examples were thenevaluated by exposing them to light and to high humidity Example 8 Thisexample illustrates the incorporation of a magenta color former in aphotographic emulsion. The particular color former used in this case hasthe formula:

(Compound 4*) aosaoss Into a Monel metal mixer vessel on a WaringBlendor (kitchen type) were poured 30 ml. of a 10% aqueous gelatinsolution. The mixer was started at 30 volts and over a period of secondswere then added 4 drops of Tergitol #4. The mixer'was run for seconds at30 volts. Into this homogeneous white emulsion was added slowly througha special funnel (containing a built-in filter and a fine tip), over aperiod of 30 seconds with the mixer running at 30 volts, a solutionconsisting of 720 mg. of the above color former in 7 ml. ofdimethylformamide and 4 drops of Tergitol NPX. The mixer was then runfor 30 seconds at 120 volts. Then, 4 drops of a aqueous solution ofsodium hydroxide were added over a period of 5 seconds with the mixerrunning at 90 volts. Mixing was continued for seconds at 90 volts. Theclear yellow product was transferred into a tray and allowed to cool.The chilled gelatinous product was cut into small noodles which wereWashed for 18 hours with cold water (8-l2 C.). The washed noodles werethen remelted at 40 C. and added to 50 g. of photographic emulsioncontaining O.6 ml. of an 8% aqueous solution of saponin as a spreadingagent. Other adjuncts such as sensitizing dyes, stabilizers, etc., maybe added at this point. The 40 C. warm mixture was then coated onto afilm support.

Samples of coatings containing the dye formed by color development usingthe color former of this example were then exposed to light and highhumidity conditions together with samples of dyes developed by the useof prior art color formers of the type having saltforming groups. Suchprior art color formers used in this test are those disclosed in U.S.P.2,200,306. The

results obtained from this test are shown in the follow- As can be seenfrom the above data, our color former yields a dye image which issuperior in overall stability to a similarly produced dye image from acoupler of the above prior art patent.

Example 9 The magenta color former of the following formula was used inthis example.

(Compound 6) into a Monel metal mixing vessel on a speed mixer (WaringBlendor, kitchen type) were placed ml. of a 10% aqueous gelatin solutionof 40 C. With the mixer running at volts, 4 drops of Tergitol #4 wereadded to the gelatin over a period of 5 seconds. The mixer was then runfor 10 seconds at 35 volts. To this homogeneous mixture was then added,by means of a special funnel, a solution of 720 mg. of the above couplerin 7 ml. of dimethylformamide and 4 drops of Tergitol NPX. The additionwas made over a period of 30 seconds with the mixer running at volts.The mixer was then run for 30 seconds at 120 volts. The product waspoured into a 8 tray and allowed to cool to room temperature. Afterchilling, the product was cut into small noodles with a knife. Thesenoodles were then washed for 18 hours with cold (812 C.) water. Afterdraining of the excess water, the noodles were remelted at 40 C. andadded in darkness to 50 g. of a color type photographic emulsion. Thisemulsion contained 0.6 ml. of an 8% aqueous solution of saponin besidesthe usual adjuncts such as sensitizing dyes, stabilizers, etc. The finalmixture was coated at 40 C. onto a photographic film support as iscustomary inthe art.

Example 10 This example illustrates a method of incorporating a yellowcolor former in a photographic emulsion. The color former used in thisexample has the formula:

oo Cameron-Q NHC o- Nnco om) ms 031%.

(Compound 7) Into a Monel metal mixer vessel on a speed mixer (WaringBlender, kitchen type) were placed 30 ml. of a 15% aqueous gelatinemulsion. The mixer was started at 30 volts and over a period of 5seconds were then added 2 drops of Pluronic L-61. The mixer was run for10 seconds at 30 volts. Then, 4 drops of Tergitol #4 were added over aperiod of 5 seconds with the mixer running at 30 volts. Mixing wascontinued for 10 seconds at 30 volts. A solution consisting of 720 ofthe above color former in 29 ml. of dimethylformamide, 4 drops ofTergitol NPX, 5 ml. of water and 6 drops of a 20% aqueous sodiumhydroxide solution was then added through a special glass funnel. Thisspecial funnel consisted of a Pyrex glass funnel of 39 mm. diameterwhose stem had been drawn out to a small opening of 1 mm. diameter. Intothe stem was packed some cotton to filter out mechanical impurities andto regulate the flowing time. The addition was made over a period of 360seconds with the mixer running at 30 volts. Mixing was continued for 30seconds with the mixer running at volts. The yellow, slightly opaqueproduct was then poured into a dish and allowed to cool. The chilledproduct was then cut into small noodles and washed for 48 hours withslow-running cold (812 C.) water. The noodles were then remelted andadded to 50 g. of a photographic emulsion. This emulsion had beendesigned for the yellow layer and contained, besides the usual finals,1.0 ml of an aqueous 8% saponin solution and 2 drops of Pluronic lr61.The mixture was then coated onto a film base as is customary in the art.

Although, in Examples 1 to 9, we have indicated the use of the customarygelatino silver halide emulsion, other water soluble colloidal materialssuitable for preparing photographic emulsions such a polyvinyl alcoholand casein, for example, can be used.

in the foregoing examples, we have referred to certain materials bytheir common trade names such as Tergitol NPX, Tergitol #4 and PluronicL-61. The identification of these materials is as follows:

Tergitol NPX is alkylphenyl polyethylene glycol ether and is sold by theCarbide and Carbon Chemical Company, 30 E. 42nd Street, New York 17, NewYork.

Tergitol #4 is sodium tetradecyl sulfate and is sold as a 25% solutionby the Carbide and Carbon Chemical Company, 30 E. 42nd Street, New York17, New York.

Pluronic L-61 is a polymer prepared by adding propylene oxide to the twohydroxyl groups or" a propylene glycol nucleus until the desiredmolecular weight is achieved. Ethylene oxide is then added to both endsof the above polymer until the desired ratio of polyoxyethylene topolyoxypro-pylene units is obtained. Pluronic L-61 is composed of apolyoxypropylene fragment with a molecular weight of 1750 while 10% ofthe total molecular weight "abscess G. 2-arnino-5-diethylamino tolueneHCI 2 Sodium sulfite, anhydrous '2 Sodium carbonate, monohydrate, '2Potassium bromide 2 Sodiumhydroxide to give .pH 10.8. Water to 1 liter.

PREPARATION OF COMPOUNDS In the synthesis of Compound 1 above, thefollowing reactions take place:

I alol NH:

s. melt;

iron reduction O O N H- potassium hydrogen ll-sulbundecanoate C O NH-vphosphor trichloride -o oNH- NHCO(CHa)1uSOsNa Reaction A was carried outin the following manner:

Apparatus1-liter round bottom flask, metal bath.

250 grams of phenyl-l-hydroxy-Z-naphthoate (0.95 M) and 119 g. ofm-nitroaniline (0.86 M) were heated for 2 hours at 150 C., 1 hour at 170C. in a metal bath (bath temp). During the last hour, the phenol wasdistilled oii at -10 mm. Hg. The cooled melt was ground with methanol ina mechanic blender, filtered on a Buchner funnel, and washed on thefunnel with methanol until the washings were nearly colorless. It wasrecrystallized from dimethylformamide containing some methanol.

Yield: 204 g. yellow needles=74%; M.P. 253 C.

Calc.: C, 66.04; H, 4.17. Found: C, 66.14; H, 4.32.

Reaction B was then carried out as follows:

Apparatus3-neck round bottom flask, stirrer, condenser and electricheatingrnantle.

200 grams of iron powder (40 mesh), ml. of hydrochloric acid, 70 ml. ofwater and 430 ml. of ethanol were combined in that order and then 30 g.(0.1 M) of the amide produced in reaction A was slowly added to therefluxing mixture. The addition oi the amide required 2 to 4 hours; anexcess oi Fe++ has to be maintained during the addition.

The mixture was refluxed overnight and then rendered alkaline againstphenolphthalein with 40% aqueous sodium hydroxide. The solution wasfiltered through a Buckner funner and the filtrate acidified withglacial acetic acid. The resulting precipitate was filtered ofi aftercoolmg.

Yield: 20 g. light red needles:74%; M.P. 196-197 C. An analytical samplewas prepared by recrystallization from acetone/ water.

1VLW. 278.29.

Cale; C, 73.36; 5.07. Found: C, -73.28; H, 5.57.

The final Compound 1 was produced by reaction C as follows:

Appar atus 500 rnl. 3-neck round bottom flask, stirrer, Dean Starkmoisture trap, condenser, calcium chloridedrying tube and droppingfunnel. 19 grams amine produced in reaction B (0.066 M).

22 grams of potassium hydrogen ll-sulfoundecanoate (1.1X0.066 M), 66 ml.of dry pyridine and 260 ml. of dry benzene were combined in the flaskand refluxed by means of an electric heating mantle until all traces ofwater were removed (req. about .2 hours). The Dean- Stark moisture trapwas then removed and the condenser exchanged fora dry one. The mixturewas cooled in an ice water bath and, with rapid stirring, a solution of6.6 m1. of phosphor trichloride in 50 ml. of dry benzene Was added. Theaddition was made dropwise and required about 1 hour. The mixture wasthen refluxed on a steam bath for 2 hours. A solution of 9 g. of sodiumhydroxide-and 20 g. of anhydrous sodium acetate in 60 ml. of water wasadded slowly and the mixture cooled in ice. The precipitate was filteredon a Buchner funnel and the last traces of pyridine removed in vacuo.The so obtained 52 g. of yellow powderous material was recrystallizedfrom acetic acid. It was then recrystallized 2 times more from the samesolvent.

Yield: 16.4 g.=45%; M.P. 284-285 C.

Cale: C, 60.31; H, 6.14; S, 5.75; N, 5.02. Found: C, 60.41; H, 6.33; S,5.74; N, 5.01.

The series of reactions for the preparation of Compound 2 maylie-represented vas follows:

(A) on salol melt ,-coo N1; N0:

I f o o NH-.- -No| G1 a on iron reducticn C ONH\ \/,"NH'

ooNH-. -Nm ooomomnosoma 0 ONHe-QNHCO cm) 108 OaNa REACTION A 1 mole(172.58 g.) of 2-chloro-4-nitro aniline and 1.1

mole (264.28 g.) of phenyl-l-hydroxy-Z-naphthoate were combined togetherin an open l-liter, l-neck round bottom flask and the mixture was heatedwithout stirring for 3 hours in a metal bath at 155-160 C. The flask wasthen connected to an oil pump vacuum and the phenol distilled ed at abath temperature of 160 C. The cold melt was then crushed andtransferred to a speed mixer (Waring Blender, kitchen type). After theaddition of 500 ml. of cold methanol, the mixer was run at full speed(120 volts) for about 5 minutes. The fine suspension was then filteredby means of a Buchner funnel and the product was washed on the funnelwith methanol until the filtrate was colorless (1500 ml. of methanol).After crystal lizing the solid once from chlorobenzene, it was filtered,sucked dry by means of an aspirator, washed again in small portions witha total of 1500 ml. of methanol, and used directly for the next reactionafter letting it dry overnight at room temperature.

REACTION B 45 grams of iron powder (40 mesh) and 15 ml. of concentratedhydrochloric acid were mixed into a 3-neck, 1- liter round bottom flaskprovided with a stirrer and a reflux condenser. After 5 minutes, 100 ml.of water and 400 ml. of ethanol were added and the mixture heated toreflux temperature with vigorous mechanical stirring. 32 grams (about0.1 mole) of the previously prepared airdried and powdered nitrocompound was then slowly added to the stirred, boiling reducing mixtureover a period of 1 hour. The suspension was then refluxed, withefficient stirring, for 18 hours. The aqueous phase was made alkalinewith aqueous, 6 N sodium hydroxide solution. After filtering from theiron-mud by means of a Buchner funnel and Filter-Col (manufactured byJohns- Manville), the filtrate was acidified with. glacial acetic acid.After cooling, the crystalline product was filtered and thenrecrystallized once from acetone. The product was air-dried andexhibited a melting point of 210 C.

REACTION C 21 grams (0.066 mole) of the above amine, 22 g. ofll-potassium sulfoundecanoic acid, 66 ml. of anhydrous pyridine and 260ml. of dry benzene were refluxed for 2 hours under a Dean-Stark moisturetrap. The flask was then cooled to C. and to the cold, stirred solutionwas slowly and carefully added dropwise a solution of 6.6 ml. ofphosphor trichloride (PCl in 50 ml. of dry benzene over a period of 1hour. The temperature during this addition was carefully kept below C.After the addition was complete, the mixture was heated to refluxtemperature and then refluxed for 2 hours with stirring. To the hotsolution was then slowly added a solution containing 9 g. of sodiumhydroxide and 20 g. of anhydrous sodium acetate in 50 ml. of water. Therate of addition depended on the speed of refluxing caused by thisexothermic reaction. After the addition was complete, which took about 5minutes, the mixture was cooled to room temperature and the solidfiltered through a Buchner funnel. The yellowish raw-product was freedfrom traces of pyridine and water by placing it into a desiccator overconcentrated sulfuric acid. The product was finely powdered and thenrecrystallized from 80% aqueous acetic acid. After tworecrystallizations, the product was white and exhibited a decompositionpoint at 287 C. Further recrystallizations did not raise thedecomposition point. The yield was 27 g. V

The ll-potassium sulfoundecanoic acid or potassium hydrogenll-sulfoundecanoate (J. Chem. Soc, 1956, p. 2560),

?0 OH sho OaNB.

used in this and the other examples was prepared as follows:

Into a 5-liter, .B-neck round bottom flask provided with stirrer andreflux condenser was charged 91 g. (0.5 mole) of undecanoic acid,

COOH

315 g. of sodium sulfite heptahydrate (Na SO -7H O), 600 ml. of ethanoland 300 ml. of water. The mixture was refluxed for 1 hour with stirring,at which time a clear solution was obtained. To the hot, stirredsolution was then added, in one portion, 500 g. of anhydrous potassiumchloride. The slurry was then cooled to 25 C. and allowed to stand for 1hour and then filtered through a B-uchner funnel. The solid was washed,on the funnel, with 200 ml. of an aqueous, 5% potassium chloridesolution, then with 200 ml. of methanol and 200 ml. of ether. The washedproduct was recrystallized once with a solution containing 400 ml. ofconcentrated hydrochloric acid, 400 ml. of water and 40 g. of potassiumchloride. The crystalline material was filtered again by means of aBuchner funnel and washed on the funnel with the following solvents:Twice with ml. each, of ice water, twice with 100 ml, each, of methanoland twice with 100 ml., each, of et er. Yields of various batches: 117g., 119 g. and 128 g.; melting point 193-197 C. The melting point rangeof the analytical sample was 195-197" C.

The preparation of Compound 3 may be represented as follows:

REACTION A OH COOMe 0H OOOMe CONH 76 grams of3-amino-5-nitromethylbenzoate (0.39 mole) and 114 g. of1-hydroxy-2-phenyl naphthoate (1.1 0.39 mole) were charged into a 500ml. round bottom flask. The mixture was heated over a period of 2 hoursto 155160 C. and then kept for 2 hours at 160 C. During the last 2hours, vacuum was applied to the flask (5-10 min/Hg.) to remove thephenol. The material was then cooled, ground with 200 ml. of methanol ina mechanical blender, filtered through a Buchner funnel and washed onthe funnel until the washings were nearly colorless. The crude productwas recrystallized from dimcthylforrnamide and methanol. Yield: g. 87%(calculated on ester); M.P. 255256 C. Anal. sample M.P. 256257 C.

C19I I14N206:366.32.

Cale: C, 62.29; H, 3.85; N, 7.65. Found: C, 62.27; H, 3.92; N, 7.58.

REACTION B (13H 0 O OMe OONH- OH COOMe CONH- I NH:

125 grams of the above nitro compound (0.34 M), g. of iron-filings (40mesh), 45 ml. of hydrochloric acid, 1400 ml. of ethanol and 250 m1. ofwater were charged into a 3-liter round bottom flask equipped with astirrer and a reflux condenser. The nitro compound produced by reactionA was added in small portions to the refluxing mixture so that an excessof Fe++ was maintained. After the addition was complete (requires about'3 'hours), the mixture was kept refluxing for another 15 hours. Themixture was then filtered, the filter cake extracted with boilingdimethylformamide and this extract combined with the filtrate which wasdiluted With water until the compound precipitated. Furtherprecipitation was completed by cooling in ice. The solid was filteredoff by means of a Buchner funnel, washed on the funnel with methanoluntil washings were nearly colorless and recrystallized from acetone.Yield: 65 g.; M.P. 240-241 C.

REACTION o H0O C (CH2) NSOSNB 50 grams of the above amine (0.165 mole),55 g. of 11-potassium sulfoundecanoic acid, 165 ml. of dry pyridine and650 ml. of dry benzene were charged in a 2- liter, 3-neck round bottomflask equipped with stirrer, Dean-Stark moisture trap, reflux condenser,calcium chloride tube and a dropping funnel. The mixture was refluxeduntil all traces of water had been removed (requires about 2 hours). Themixture was cooled with ice water and a solution of 16.5 ml. of phosphortrichloride in 50 ml. of dry benzene was added dropwise under rapidstirring (requires about 1 hour), followed by refluxing for 2 hours on a'steam bath. To the hot solution was added a solution of 30 g. of sodiumhydroxide and 35 g. of anhydrous sodium acetate in 200 ml. of water andthe reaction cooled to 0 C. in a refrigerator for 15 hours. The solidwas filtered and dried over sulfuric acid in a vacuum desiccator andrecrystallized from 80% acetic acid and then 3 times from 70% methanol.Yield 50 g.

Cale: C, 57.03; H, 5.61; S, 5.25; N, 4.59. Found: C, 57.12; H, 6 .16; S,5.14; N, 4.54.

The preparation of compound 4 may be represented as follows:

REACTION A 176 grams of 3-amino-l-phenylpyrazolone-S (1 mole) wereslurried in a 2-liter round bottom flask With 600 ml. dry pyridine. Tothis was added a slurry of 186 g. of m-nitrobenzoylchloride (1 mole) in200 ml. 'of dry benzene. After the main reaction has subsided, themixture was heated on a steam bath for hours and then poured in 2-litersof ice water, filtered and recrystallized from dimethylformamide andmethanol.

The product obtained was:

53% yield 174 g.; M.P. 226-227 C.; Anal. sample Ml. 227-228 C.

Calc.: C, 59.08; H, 4.027; N, 17.22. Found: C, 59.74; H, 4.30; N, 17.22.

14 REACTION B 400 grams of iron powder (40 mesh), 135 ml. ofhydrochloric acid, 800 ml. of water and 3200- rnl. of ethanol werecombined in .this order in a 5-liter, 3-neck flask equipped with stirrerand reflux condenser. After the mixture started refluxing, 174 g. of thecompound (0.535 mole) (from reaction A) was added in small portions,always maintaining an excess of Fe++. Thisrequired about 3-4 hours. Themixture was kept refluxing for 15 hours, then made basic with 50% sodiumhydroxide (phenolphthalein as indicator). It was filtered .by means of aBuchner funnel, the filtrate acidified with glacial acetic acid andcooled. The crystalline precipitate was filtered off and washed oncewith methanol. 73% yield 117 g.; MP. 225226'C. Anal. sample M1. 227- 228C.

The product obtained was:

CONHCCH2 C H N O =2953L Cale: C, 65.08; H, 5.12; N, 18.97. Found: C,65.33; H, 6.77; N, 18.81.

REACTION C 117 grams of the above amine (0.395 mole), 130 g. ofpotassium hydrogen ll-sulfoundecanoate (1.l 0.395 mole), 395 ml. of drypyridine and 1500 ml. of dry benzene were charged in a 3- neck, 3-literround bottom flask equipped with stirrer, Dean-Stark moisture trap,dropping funnel, condenser, and a calcium chloride drying tube. Themixture was refluxed until all traces of water were removed (about 2hours). After cooling the flask in ice water with rapid stirrin asolution of 18 ml. of phosphor trich loride (PCI in 200 ml. of drybenzene was added dropwise over a period of 1 hour and then kept atreflux temperature on a steam bath for 2 hours. To the hot mixture wasadded a solution of 31 g. of sodium'hydroxide and g. of anhydrous sodiumacetate in 200 m1. of water. The flask was then cooled to 0 C. and keptin a refrigerator for 15 hours. The resulting solid was filtered'bymeans of a Buchner funnel and dried in a vacuum desiccator over sulfuricacid. It was once recrystallized from acetic acid and then twice from70% methanol. Yield g.

The product obtained Was:

CONHGCH1 SOaNa(CHz) 106 ()NH (Compound 4) spouses 40 ml. of dry benzeneadded dropwise with rapid stirring. This required about 1 hour. Themixture was refluxed for 2 hours on a steam bath and to the still hotmixture was added a solution of 4.5 g. of sodium hydroxide and 11 g. ofsodium acetate (anhydrous) in 40 ml. of water. The mixture was thencooled, filtered and dried in a vacuum desiccator over concentratedsulfuric acid. The product was purified by dissolving it in 250 ml. ofhot 70% methanol which had previously been adjusted to a pH of 9 with 2N sodium hydroxide and precipitating it with 5 N hydrochloric acid afterfiltration.

The above 3-(rn-aminobenzamido)-l-(2,4,6 -tricl1lorophenyDpyrazolone-Swas obtained by the acylation of 3-amino-1-(2,4,6-trichlorophenyl)pyrazolone-S with m-nitrobenzoyl halidein pyridine solvent. The resulting 3- (m-nitrobenzamido)pyrazolone-S wasthen reduced to the corresponding amino compound by catalytichydrogenation using Raney nickel as a catalyst.

The preparation of Compound 6 may be represented as follows:

18 grams of 3-amino-l-phenylpyrazolone-S, 31 g. of potassium hydrogenll-sulfoundecanoate, 60 ml. of dry pyridine and 260 ml. of dry benzenewere charged in a l-liter, 3-neck round bottom flask equipped withstirrer, Dean-Stark moisture trap, dropping funnel, condenser andcalcium chloride tubing. The mixture was refluxed until all traces ofwater were removed, then cooled in an ice water bath and a solution of4.5 ml. of phosphor trichloride in 50 m1. of dry benzene was slowlyadded. This addition was made dropwise and required about 1 hour. Themixture was refluxed for 2 hours on a steam bath and a solution of 8 g.of sodium hydroxide and 21 g. of anhydrous sodium acetate in 50 ml. ofwater was added to the hot mixture. The flask was stored in arefrigerator for hours and the contents then filtered on a Buchnerfunnel and dried in a vacuum desiccator over sulfuric acid.Recrystallization from three times 80% acetic acid. Yield 23 g. ofpurified product.

02110.: C, 53.92; H, 6.34; N, 9.43; S, 7.19. Found: C, 54.75; H, 8.04;N, 9.59; S, 6.74.

The preparation of Compound 7 may be represented as follows:

REACTION A 96 grams of 1-amino-a-benzoylacetanilide were slur-tied in200 ml. of dry benzene and a slurry of 71 g. of p-nitrobenzoylchloridein 400 ml. of pyridine was added. The mixture was heated for 5 hours ona steam bath, then the pyridine removed by vacuum distillation. Theresidue was recrystallized from a mixture of dimethylformamide andmethanol.

The compound produced was:

Yield 170 'g.; MP. 258259 C.

Cale; C, 65.34; H, 4.23; N, 10.39. Found: C, 65.73; H, 4.26; N, 10.63.

REACTION B 300 grams of iron powder (40 mesh), 160 ml. of hydrochloricacid, 400 ml. of water and 2000 ml. of ethanol were charged in a3-liter, 3-neck round bottom flask equipped with stirrer and refluxcondenser. To the refluxing mixture, 170 g. of the above nitro compoundfrom reaction A was added in small portions, always maintaining anexcess of Fe++. The mixture was refluxed overnight, rendered alkalineagainst phenolphthalein with 50% sodium hydroxide, filtered andacidified with dry acetic acid. The nearly white precipitate wasfiltered ofii.

The compound produced was:

Yield 50 g.; M.P. 238241 C. (32110.: C, 70.77; H, 5.13; N, 11.26. Found:C, 70.3; H, 5.14; N, 11.98.

REACTION C 56.5 g. of the above amine from reaction B, 49.5 g. ofpotassium hydrogen ll-suifoundecanoate, 151 ml. of dry pyridine and 570ml. of dry benzene were charged into a l-liter, S-neck flask equippedwtih stirrer, Dean-Stark moisture trap, reflux condenser, calciumchloride tube and a dropping funnel. The mixture was refluxed until alltraces of water were removed (requires about 2 hours). The mixture wasthen cooled in an ice water bath and a solution of 7 ml. of phosphortrichloride in 50 ml. of dry benzene was added dropwise under rapidstirring. The addition required about 1 hour. The mixture was refluxedon a steam bath for 2 hours. Then, a solution of 12 g. of sodiumhydroxide and 30 g. of sodium acetate in 50 ml. of water was added. Thereaction product was stored for 15 hours in a refrigerator, filtered ona Buchner funnel and recrystallized from acetic acid.

The compound produced was:

(Compound 7) a Our invention is not limited to the detailed descriptioncontained herein, but includes all modifications that fall within thescope of the appended claims.

We claim:

1. The method of incorporating in a photographic silver halidehydrophilic emulsion a salt of a color coupler of the following formula:

C O-NH-R (CH2)n-1 SOaM wherein M is selected from the class consistingof ammonium and an alkali metal, R represents a coupler molecule of thetype capable of coupling with the oxidation prod ucts of a primaryaromatic amino developing agent, said coupler molecule being selectedfrom the class consisting f l-hydroxy-Z-naphthoic radicals, OL-bCl'lZOylacid anilide radicals, and 3-(l-phenyl-S-pyrazolone) radicals and nrepresents a positive integer of at least 9 which comprises dissolvingsaid coupler salt in dimethylformamide, mixing the resulting solution ofsaid coupler with a solution of the hydrophilic colloid used in thepreparation of the hydrophilic emulsion, setting the resultingdispersion, shredding the set dispersion, washing the shredded setdispersion to remove the dimethylformamide therefrom and mixing thewashed dispersion with the said photographic silver halide hydrophilic,emulsion in order to form a mixture of said coupler salt in saidgelatino silver halide emulsion.

2. The method as recited in claim 1 wherein the photographic silverhalide hydrophilic emulsion is a photographic gelatino silver halideemulsion.

References Cited in the file of this patent UNITED STATES PATENTS2,498,466 Thompson Feb. 21, 1950 2,533,514 Sawdey et al Dec. 12, 19502,829,975 Popeck et al Apr. 8, 1958 2,902,366 Sprung et a1 Sept. 1, 1958

1. THE METHOD OF INCORPORATING IN A PHOTOGRAPHIC SILVER HALIDE HYDROPHILIC EMULSION A SALT OF A COLOR COUPLER OF THE FOLLOWING FORMULA: 